Fundamentals of Colloidal Bimetallic Nanoparticle Catalysts

The Pd-on-Au NPs currently investigated for the catalytic reduction of organic halides dissolved in water are highly useful as a model catalytic material to study in greater detail (i) the effects of mass transfer on reaction kinetics), (ii) the bi-metal distribution of the core/shell nanostructure, (iii) the nature of the catalytically active sites, and (iv) the details of the surface reaction pathway. We have successfully addressed these questions through the development of new spectroscopic techniques (gold nanoshell-based surface enhanced Raman spectroscopy and in situ x-ray absorption spectroscopy), careful synthesis methods, and the application of classical reaction kinetics analysis (e.g., experimental identification of mass transfer resistances and Langmuir-Hinshelwood mechanistic studies). Our research team and collaborators continue to deepen our understanding of bimetallic catalysts.